CN115702072A

CN115702072A - Plastic container for packaging oxygen sensitive products and method of making same

Info

Publication number: CN115702072A
Application number: CN202180041627.XA
Authority: CN
Inventors: 迈赫迪·萨涅伊; 马克·E·林登费尔泽; 埃里克·V·弗雷德里克森
Original assignee: MuCell Extrusion LLC
Current assignee: MuCell Extrusion LLC
Priority date: 2020-04-16
Filing date: 2021-04-16
Publication date: 2023-02-14
Also published as: KR20230011943A; EP4135964A4; WO2021211968A1; US20210339923A1; JP2023522048A; EP4135964A1

Abstract

Plastic containers and methods of forming the same are described. In some cases, the container is a recyclable, multi-layer extrusion blow molded plastic container comprising high density polyethylene having enhanced oxygen barrier properties. The containers may be used for direct and indirect food contact packaging applications, liquid packaging applications, and for aseptic packaging applications. The container may have an oxygen transmission rate according to ASTM D3985 of less than 10cc/m ² Day. The vessel may be recycled in the HOPE recycle stream.

Description

Plastic container for packaging oxygen sensitive products and method of making same

RELATED APPLICATIONS

This application claims priority to U.S. provisional patent application No. 63/010,891, filed on 16/4/2020, which is incorporated herein by reference in its entirety.

Technical Field

The present invention relates to multilayer (e.g., extrusion blow molded) containers that may be used, for example, for packaging oxygen sensitive products.

Background

As food consumers' expectations for the quality of the food itself, as well as the quality of packaging, increase, food producers and packaging companies face greater challenges in providing healthy and fresh food products to the market with minimal or no chemical preservatives and with favorable packaging quality. Developing new technologies that can significantly contribute to preserving edible products over longer periods of time is critical in the shelf life of food products in supply chains and stores. This is because many food products are susceptible to rancidity or degradation when they are exposed to oxygen. For example, raw milk deteriorates in just a few days, even when stored at refrigerated temperatures. Milk pasteurized at High Temperature for Short Time (HTST) may have a shelf life of 7 to 28 days if stored refrigerated. Clearly, any poor cold chain conditions (which subject the milk to repeated and/or sometimes severe temperature abuse) that may often occur during the supply chain can significantly shorten shelf life.

Strict control of the temperature after pasteurization and the aseptic system used for bottling can increase the shelf life of the pasteurized milk. The advent of paper-foil-plastic laminated containers, such as Tetrahedron in 1959, is a turning point in the aseptic packaging industry. Therefore, a layer of metallised polymer film or aluminium film is typically incorporated into the structure of the paperboard, which provides excellent oxygen barrier properties. On the other hand, existing non-metallized multi-layer blow molded High Density Polyethylene (HDPE) containers have one or more layers made of ethylene vinyl alcohol (EVOH). Although these EVOH layers may exhibit suitable oxygen barrier properties, they may contaminate the HDPE single material stream for recycling.

Accordingly, it would be beneficial to develop a recyclable, blow-molded HDPE container that exhibits enhanced oxygen barrier properties that can be used to store oxygen-sensitive products.

Disclosure of Invention

Plastic containers and methods for forming the same are described herein.

In some aspects, a multilayer plastic container is provided. The container includes at least three layers including one or more inner layers between two solid skin layers. The solid skin layer comprises Polyethylene (PE). At least one of the inner layers comprises a PE/EVOH blend. The blend includes about 30 to 50 weight percent EVOH, and the total amount of EVOH in the container is no more than 10 percent of the weight of the container.

In some aspects, a method of forming a multi-layer plastic container comprising at least three layers including one or more inner layers between two solid skin layers is provided. The method comprises the following steps: a first fluid stream of a polymeric material comprising polyethylene is processed in a first extruder, and a second fluid stream of a second polymeric material comprising a blend of an olefin resin and EVOH is processed in a second extruder. The blend comprises about 30 weight percent to about 50 weight percent EVOH. The method also includes coextruding a first fluid stream and a second fluid stream through a parison mold to form a multi-layer parison comprising two polyethylene layers and a layer comprising a second polymeric material. The method also includes blow molding the parison into a mold or vessel to form a container. The container includes at least three layers including one or more inner layers between two solid skin layers. One or more of the inner layers comprises a second polymeric material and both solid skin layers comprise polyethylene.

In some embodiments, the product may have an oxygen transmission rate according to ASTM D3985 of less than 10cc/m ² And/24 hours.

In some embodiments, the product may have a water vapor transmission rate according to ASTM E398-13 of less than 2 grams/m ² And/24 hours.

Other aspects, embodiments, advantages, and features may become apparent from the following detailed description.

Detailed Description

The singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

All ranges disclosed herein are inclusive of the recited endpoint and independently combinable (e.g., ranges of 30 weight percent to 50 weight percent EVOH content are inclusive of the endpoints 30 and 50, and all intermediate values, in the same context, e.g., less than 50 weight percent total EVOH content is inclusive of the endpoint 50 weight%)

As used herein, approximating language may be applied to modify any quantitative representation that may vary without resulting in a change in the basic function to which it is related. Accordingly, a value modified by a term or terms, such as "about" and "substantially," may not be limited to the precise value specified. The modifier "about" should also be considered as disclosing the range defined by the absolute values of the two endpoints. For example, the expression "about 30 to about 50" also discloses a range of "30 to 50".

As used herein, the term "container" also includes bottles, and both terms also include tapered neck forms and non-tapered neck forms.

As used herein, the term "skin layer" refers to the two outermost layers of a multilayer structure. For a container, one skin defines the outer surface of the container and one skin defines the inner surface of the container. The term "inner layer" refers to the layer between the skin layers.

The present disclosure relates to multilayer (e.g., extrusion blow molded) containers suitable for use in: oxygen sensitive products and food products, e.g., pasteurized products; infant food products; liquid foods and beverages (e.g., water, juice beverages, cold-brewed coffee and all kinds of coffee-like beverages, all kinds of iced tea and herbal beverages, bouillons, soups, milk and all kinds of products derived from milk); a concentrate; all kinds of condiments, such as tomato paste; liquid eggs; all kinds of edible oils (e.g. olive oil, vegetable oil, rapeseed oil); and packaging of tomato products; packaging for dry food products such as biscuits, cookies, cereals, various nuts, tea, coffee, sugar, flour, dry food mixes, chocolate, candies, pet food. The containers described herein may be used for aseptic packaging of any kind of beverage or liquid food that may be stored at room temperature. The containers described herein may be used for modified atmosphere packaging. The container can also be used for packaging all kinds of laundry detergents, shampoos and body lotions. The container described herein can be used for packaging drinking water, all kinds of vitamin beverages and caffeine containing beverages. The products described in all embodiments can be used for, but are not limited to, packaging of all kinds of oxygen sensitive chemicals, petroleum jars, corrosive chemicals and motor oils.

The above examples do not have any limitation on the application of the products of the present disclosure, and other applications may be possible.

Disclosed herein are recyclable plastic containers with enhanced oxygen barrier properties that are manufactured using an extrusion blow molding process in which a parison comprising one or more layers is blow molded into a vessel or mold to form the container. The container is formed from a multilayer parison formed in a coextrusion process in which a combination of multiple extruders is used. The multilayer container comprises Polyethylene (PE), such as HDPE. Typically, the multilayer container includes one or more inner layers formed between two solid skin layers, wherein at least one inner layer (and in some cases, all inner layers) is a polymer blend of PE/ethylene vinyl alcohol (EVOH) (e.g., HDPE/EVOH) that includes up to 50 weight percent EVOH, for example, about 30 to 50 weight percent, in some cases about 35 to 50 weight percent, in some cases about 40 to 50 weight percent, in some cases about 45 to 50 weight percent, and the total amount of EVOH in the overall structure of one unit product does not exceed 10 percent of the weight of the product. In some embodiments, the total amount of EVOH in the structure of the container is no more than 5 percent of the weight of the container, and in some embodiments, the total amount of EVOH in the structure of the container is no more than 2.5 percent of the weight of the container.

In some embodiments, the blow molded products described herein comprise one or more layers, wherein at least one layer comprises from about 30 weight percent to about 50 weight percent EVOH, and comprises less than 5 weight percent EVOH per unit of product.

In some embodiments, a blow molded container described herein comprises one or more foam layers (e.g., between two solid skin layers). In some embodiments, the blow molded containers described herein comprise one or more solid layers (e.g., between solid skin layers), wherein the one or more solid inner layers comprise from about 30 weight percent to about 50 weight percent EVOH, in some cases from about 40 weight percent to about 50 weight percent, in some cases from about 45 weight percent to about 50 weight percent, and the total amount of EVOH in the structure of the container is no more than 10 percent of the weight of the container.

In some embodiments, the total amount of EVOH in the structure of the container is no more than 5 percent of the weight of the container, and in some embodiments, the total amount of EVOH in the structure of the container is no more than 2.5 percent of the weight of the container.

In some embodiments, at least 10% of the cells are closed cells; in some embodiments, more than 50% of the cells are closed cells; and in some embodiments, more than 75% of the cells are closed cells. As used herein, "closed cell" refers to a cell that is: it has a pore wall that completely surrounds the pore without openings so that there is no interconnection with adjacent pores.

In some embodiments, the multilayer products described herein comprise seven (or at least seven) layers; in some embodiments, there are six (or at least six) layers; in some embodiments, there are five (or at least five) layers; in some embodiments, there are four (or at least four) layers; in some embodiments, there are three (or at least three) layers; in some embodiments, there are two (or at least two) layers, and in some embodiments, the product is a single layer. For example, a seven-layer product includes one or more layers (e.g., inner layers) comprising up to 50 weight percent EVOH, wherein the amount of EVOH does not exceed 10 percent of the product weight throughout the structure. In some other embodiments, a six-layer product includes one or more layers (e.g., inner layers) comprising up to 50 weight percent EVOH, wherein the amount of EVOH does not exceed 10 percent of the product weight in the overall structure. In some cases, three-layer products include up to about 30 to about 50 weight percent EVOH in the middle layer, wherein the amount of EVOH in the overall structure is no more than 10 percent of the product weight. In one instance, the single layer product comprises up to 50 weight percent EVOH. In another embodiment, the products described herein, which may be seven, six, five, four or three layers, include at least one inner foam layer, and/or in some cases one inner solid layer, and two outer solid layers. In some other embodiments, the product comprises five or four layers. It should be understood that other layer configurations may be possible.

In some embodiments, the products described herein are single layers comprising PE/EVOH blends and may be manufactured using an injection blow molding process, wherein the content of EVOH is less than 50 weight percent.

Embodiments of the recyclable multi-layer products, such as containers, described herein may exhibit enhanced oxygen barrier properties as compared to conventional products. In some embodiments, the product has an oxygen transmission rate of less than 20cc/m according to ASTM D3985 ² A day; in some cases, less than 15cc/m ² A day; in some cases, less than 10cc/m ² A day; in some cases, less than 5cc/m ² A day; in some cases, less than 2cc/m ² A day; and in some cases, less than 1cc/m ² The day is.

In some embodiments, the product may have less than 5 grams/m according to ASTM E398-13 ² Water vapor transmission rate per day; in some other cases, less than 2 grams/m ² Water vapor transmission rate per day; and in some cases, less than 1 gram/m ² The day is one.

In some casesIn an embodiment, the described product comprises at least one layer comprising a resin having an oxygen transmission rate value according to ASTM D3985 of less than 10cc/m ² Day/mil. In another embodiment, the described product may have at least one layer comprising a polymer blend comprising ethylene vinyl alcohol (EVOH) in addition to the solid skin layer.

In some embodiments, the products described herein are lightweight and have less than 1 gram/cm ³ The bulk density of (a).

In some embodiments, at least one layer (e.g., skin layer, at least one inner layer, all inner layers) of a described product, e.g., a container, comprises HDPE. In some cases, the polymeric material in one or more of the layers consists essentially of HDPE, and in some cases, the polymeric material in at least one of the solid layers (except for the solid skin layer) comprises EVOH. In some embodiments, the total amount of EVOH in the containers described herein does not exceed 10 percent of the total weight of the same container. In some embodiments, the total amount of EVOH in the structure of the container is no more than 5 percent of the weight of the container, and in some embodiments, the total amount of EVOH in the structure of the container is no more than 2.5 percent of the weight of the container. In one embodiment, at least one layer of the multilayer film may comprise LDPE.

In some embodiments, the monolayer containers described herein may be produced by an extrusion blow molding process, an injection blow molding process, or other suitable methods.

In some embodiments, the polymer composition of each layer may include some suitable amount of other additives, such as pigments, slip agents, antistatic agents, UV stabilizers, antioxidants, nucleating agents, or clarifying agents.

In some embodiments, at least one layer comprises less than 20 weight percent of inorganic additives, such as talc. In some embodiments, at least one layer comprises less than 15 weight percent; in some embodiments, less than 10 weight percent; and in some embodiments less than 5 weight percent of an inorganic additive, such as talc. In some other embodiments, at least one layer comprises less than 40 weight percent of an inorganic additive, e.g., a clay or nanoclay; in some embodiments, less than 30 weight percent; in some embodiments, less than 15 weight percent; and in some embodiments, less than 5 weight percent.

In some embodiments, one or more layers of the products described herein comprise less than 5 weight percent Maleic Anhydride (MA); in some embodiments, less than 3 weight percent MA; and in some embodiments, less than about 1 weight percent MA.

In some embodiments, the foam layer optionally may include 0.05 to 15 weight percent of an inorganic additive, an organic additive, or a mixture of an inorganic additive and an organic additive as a nucleating agent. In some embodiments, the foam layer optionally may comprise about 1 to 15 weight percent; in some embodiments, about 2.5 to 15 weight percent; in some embodiments, about 5 to 15 weight percent; in some embodiments, about 7.5 to 15 weight percent; in some embodiments, about 10 to 15 weight percent; and in some embodiments, about 12.5 to 15 weight percent of an inorganic additive, an organic additive, or a mixture of an organic additive and an inorganic additive as a nucleating agent. For example, the foam layer may contain up to about 15 wt% talc as a nucleating agent. In some embodiments, at least one layer may comprise a clarifying agent in less than 1 weight percent, such as less than 0.5 weight percent, such as less than 0.1 weight percent, such as less than 0.05 weight percent. In some cases, at least one layer of the film may comprise up to about 35% by weight calcium carbonate. In another exemplary embodiment, the outer skin layer of the product may comprise up to about 25% by weight talc.

In some embodiments, the skin layer of a container described herein is a solid layer comprising HDPE. In some embodiments, the innermost skin layer of the container (e.g., the layer of the container that will be in direct contact with the contents in the container (e.g., a food product)) is a solid layer comprising FDA-approved HDPE.

In some cases, a multilayer container described herein can include two solid skin layers, wherein at least one of the skin layers comprises an amount of black pigment, e.g., less than 1 weight percent, and the other solid skin layer can comprise an amount of white pigment, e.g., less than 1 weight percent; in some cases, both solid skin layers contain some amount of white pigment. In some cases, at least one of the layers of the multilayer containers described herein comprises a black pigment.

In some embodiments, the total thickness of the products described herein may be greater than 10 mils, in some cases greater than 12 mils, in some cases greater than 15 mils, and in some cases greater than 20 mils. In some other embodiments, other layer thicknesses less than 10 mils with the described layer configurations may be possible. In some embodiments, the total thickness of the product is less than 25 mils.

In some embodiments, the thickness of the foam layer in the disclosed products is less than 500 μm, in some embodiments, less than 350 μm, in some embodiments, less than 250 μm, in some embodiments, less than 200 μm, and in some embodiments, less than 100 μm.

In some embodiments of the disclosed products, the thickness of the layer comprising EVOH is less than 250 μm, in some embodiments, less than 200 μm, in some embodiments, less than 150 μm, in some embodiments, less than 100 μm, and in some embodiments, less than 50 μm.

In some embodiments, the foam layer of the disclosed lightweight products can have a uniform distribution of cells, e.g., having a closed cell morphology, an average cell size of about 10 μm to 250 μm, about 10 ² Hole/cm ³ To 10 ⁹ Hole/cm ³ And an average cell density relative to an unfoamed volume of 1 to 9. In some embodiments, the average cell size of the cells in the foam layer is less than 250 μm, in some embodiments less than 200 μm, in some embodimentsLess than 150 μm, in some embodiments less than 100 μm, in some embodiments 75 μm, and in some embodiments less than 50 μm. In some cases, the average cell size of the cells in the foam is greater than 10 μm (e.g., greater than 10 μm and less than 100 μm). In some cases, the foam layer contains more than 50% closed cells, in some cases, more than 75% closed cells, in some cases, more than 85% closed cells, and in some cases, more than 90% closed cells. In one embodiment, the foam layer has a substantially fully closed cell morphology (e.g., more than 95% closed cells). In some embodiments, the foam layer of the disclosed lightweight products has a density of less than 0.99 g/cm ³ And in some cases, less than 0.85 g/cm ³ And in some cases, less than 0.75 g/cm ³ In some cases, less than 0.65 grams/cm ³ And in some cases, less than 0.55 g/cm ³ And in some cases, less than 0.45 g/cm ³ In some cases, less than 0.35 g/cm ³ And in some cases, less than 0.25 g/cm ³ And in some cases, less than 0.15 g/cm ³ And in some cases, less than 0.1g/cm ³ . In some embodiments, the foam layer of the disclosed lightweight products has a density of about 0.1 grams/cm ³ To 0.95 g/cm ³ And in some cases, about 0.2 g/cm ³ To 0.95 g/cm ³ And in some cases, about 0.3 g/cm ³ To 0.95 g/cm ³ And in some cases, about 0.4 g/cm ³ To 0.95 g/cm ³ And in some cases, about 0.5 g/cm ³ To 0.95 g/cm ³ And in some cases, about 0.6 g/cm ³ To 0.95 g/cm ³ And in some cases, about 0.7 g/cm ³ To 0.95 g/cm ³ And in some cases, about 0.8 g/cm ³ To 0.95 g/cm ³ And in some cases, about 0.9g/cm ³ To 0.99 g/cm ³ 。

In some embodiments, at least one layer of the multilayer products described herein comprises a Polyethylene (PE), such as HDPE, LDPE, LLDPE copolymers (said polyethylene comprising an alpha-olefin comonomer, such as butene, hexene, octene) or polypropylene (PP). In some embodiments, at least one layer of the multilayer products described herein preferably comprises HDPE.

In some embodiments, at least one layer of a multilayer product described herein comprises from about 0 wt% to about 100 wt% recycled material, e.g., a HDPE, a post-consumer regrind material, e.g., a PCR HDPE, or a post-industrial regrind material, e.g., a HDPE. In some embodiments, at least one layer of the multilayer products described herein comprises from about 10% to about 100% by weight recycled material, in some embodiments from about 25% to about 100% by weight recycled material, in some embodiments from about 50% to about 100% by weight recycled material, in some embodiments, from about 75% to about 100% by weight recycled material, in some embodiments, from about 85% to about 100% by weight recycled material, and in some embodiments, from about 95% to about 100% by weight recycled material.

In some embodiments, at least one layer of the multilayer products described herein comprises Ethylene Vinyl Acetate (EVA), ethylene vinyl alcohol (EVOH), polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), polyamide (PA), polyethylene terephthalate (PET), any resin known to be the TPE family (such as, but not limited to, propylene-ethylene copolymers, thermoplastic olefins (TPO), and Thermoplastic Polyurethanes (TPU)).

In another embodiment, at least one layer of the product (e.g., other than the outer skin layer) may comprise LDPE, PP, PA, EVOH, EVA, or PVOH.

Disclosed herein is a method of making a recyclable, blow-molded multilayer container, the method comprising: processing a first fluid stream of a polymeric material comprising an olefin resin (e.g., PE) in an extruder; processing a second fluid stream of a second polymeric material comprising a blend of an olefin resin and EVOH (e.g., PE/EVOH) in an extruder, wherein the blend comprises from about 30 weight percent to about 50 weight percent EVOH; and co-extruding the first fluid stream and the second fluid stream through a parison mold to form a multilayer parison comprising a polyethylene layer and a layer comprising a second polymeric material, and the concentration of EVOH in a total throughput stream (throughput flow) may be less than 10 weight percent, for example, in a combined material processed per pound per inch of parison mold per hour; the resulting parison is then blown into a mold or vessel to form a container. In some embodiments, the total amount of EVOH in the total throughput stream is less than 5 percent, and in some embodiments, less than 2.5 percent, per pound of combined material processed per inch of parison mold per hour.

Disclosed herein is a method of making a lightweight recyclable blow-molded multilayer container, the method comprising: processing a first fluid stream of a polymeric material comprising an olefin resin (e.g., PE) in an extruder; processing a second fluid stream of a second polymeric material comprising a blend of an olefin resin and EVOH (e.g., PE/EVOH) in an extruder, wherein the blend comprises about 30 weight percent to about 50 weight percent EVOH, wherein a supercritical physical blowing agent is introduced into the first fluid stream and/or the second fluid stream in the extruder; and co-extruding the first fluid stream and the second fluid stream through a parison mold to form a multilayer parison comprising at least one foam layer and a concentration of EVOH in the total throughput stream of less than 10 weight percent per pound per inch of combined material processed per hour of the parison mold; the resulting parison is then blown into a mold or vessel to form a container. In some embodiments, the total amount of EVOH in the total throughput stream is less than 5 percent in the combined material processed per pound per inch of parison mold per hour; and in some embodiments, the total amount of EVOH is less than 2.5 percent.

In some embodiments, the blowing agent used in the method of making the described lightweight products can be N ₂ 、CO ₂ ，N ₂ And CO ₂ Or any other chemical blowing agent known in the art.

Claims

1. A multilayer plastic container comprising at least three layers including one or more inner layers between two solid skin layers, wherein the solid skin layers comprise Polyethylene (PE), wherein at least one of the inner layers comprises a PE/EVOH blend comprising about 30 to 50 weight percent EVOH, and the total amount of EVOH in the container is no more than 10 percent of the weight of the container.

2. The container of claim 1, wherein the blend is HDPE/EVOH and comprises about 45 to 50 weight percent EVOH.

3. The container of any preceding claim, wherein the container has an oxygen transmission rate of less than 10cc/m according to ASTM D3985 ² And/24 hours.

4. The container according to any preceding claim, wherein at least one layer comprises further additives to comprise pigments, slip agents, antistatic agents, UV stabilizers, maleic anhydride and antioxidants.

5. A container according to any preceding claim, comprising one or more foam layers, wherein at least 10% of the cells in one or more foam layers are closed cells.

6. The container of any preceding claim, comprising one or more foam layers, wherein the thickness of the one or more foam layers is less than 500 μ ι η.

7. The container according to any preceding claim, wherein the thickness of the one or more inner layers comprising the PE/EVOH blend is less than 100 μ ι η.

8. The container of any preceding claim, wherein one or more layers comprise about 10% to 100% recycled polyethylene.

9. The container of any preceding claim, comprising a foam layer, wherein the foam layer comprises an inorganic additive, an organic additive, or a mixture of both as a nucleating agent.

10. The container of any preceding claim, comprising a foam layer, wherein the foam layer comprises a nucleating agent in an amount of 0.05 to 15 weight percent of an inorganic additive, an organic additive, or a mixture of an inorganic additive and an organic additive.

11. The container of any preceding claim, comprising a foam layer, wherein the average cell size in the foam layer is about 10 to 100 μ ι η.

12. The container of any preceding claim, comprising a foam layer, wherein the cell density relative to the unfoamed volume in the foam layer is 10 ² Hole/cm ³ To 10 ⁹ Hole/cm ³ 。

13. The container of any preceding claim, comprising a foam layer, wherein the foam layer has a density of about 0.1g/cm ³ To 0.9g/cm ³ 。

14. A method of manufacturing a multilayer plastic container comprising at least three layers including one or more inner layers between two solid skin layers, the method comprising:

processing a first fluid stream of polymeric material comprising polyethylene in a first extruder;

processing a second fluid stream of a second polymeric material comprising a blend of an olefin resin and EVOH in a second extruder, wherein the blend comprises from about 30 weight percent to about 50 weight percent EVOH; and

coextruding the first fluid stream and the second fluid stream through a parison mold to form a multilayer parison comprising two polyethylene layers and a layer comprising the second polymeric material; and

blow molding the parison into a mold or vessel to form a container, wherein the container comprises at least three layers including one or more inner layers between two solid skin layers, wherein the one or more inner layers comprise the second polymeric material and the two solid skin layers comprise polyethylene.

15. A method of manufacturing a multilayer plastic container according to claim 14, wherein the second polymeric material comprises an HDPE/EVOH blend comprising about 45 to 50 weight percent EVOH.

16. The method of manufacturing a multilayer container according to claims 14 and 15, wherein the container is recyclable, and wherein a supercritical physical blowing agent is introduced into the first fluid stream and/or the second fluid stream in the extruder; and co-extruding the first fluid stream and the second fluid stream through a parison die to form a multi-layer parison comprising at least one foam layer; the resulting parison is then blown into a mold or vessel to form a container.

17. The method of making a multilayer container according to claims 14 to 16, wherein the concentration of EVOH in the total throughput stream is less than 10 weight percent in combined materials processed per pound per inch of the parison mold per hour.

18. A method of manufacturing a multilayer container according to claim 16, wherein the supercritical blowing agent is supercritical nitrogen or supercritical carbon dioxide, or a mixture of both.